Power Control Method and Apparatus

ABSTRACT

A method includes obtaining a power control parameter for a sounding reference signal (SRS), where the power control parameter for the SRS includes at least one of a target power parameter value for the SRS, a path loss compensation factor, and a closed-loop power control parameter value for the SRS. The method further includes determining transmit power for the SRS on a first carrier based on the power control parameter for the SRS.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/301,102 filed on Nov. 13, 2018, which is a National Stage ofInternational Patent Application No. PCT/CN2016/082122 filed on May 13,2016. Both of the aforementioned applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

Embodiments of the present disclosure relate to communicationstechnologies, and in particular, to a power control method andapparatus.

BACKGROUND

In order to increase system transmission bandwidth, a carrieraggregation technology is introduced into a Long Term Evolution Advanced(LTE-A) system.

During carrier aggregation, user equipment (UE) usually can aggregate alarger quantity of downlink carriers, while a much smaller quantity ofuplink carriers. Generally, based on channel non-reciprocity, formeasurement of some downlink channels, measurement of the downlinkchannel is obtained using a channel non-reciprocity feature, forexample, a precoding matrix index (PMI) and an uplink sounding referencesignal (SRS). Because UE's downlink carrier aggregation capacity isgreater than its uplink carrier aggregation capacity, no uplinktransmission is present on some time division duplex (TDD) carriers fordownlink transmission of the UE. To ensure timely SRS transmission,carrier switching is required. For example, in a first subframe, acarrier 1 and a carrier 2 are used for downlink transmission. When SRStransmission is required in a second subframe, carrier switching isperformed. The carrier 2 is changed to a carrier 3 and the carrier 3 isused to transmit the SRS. In addition, transmit power for the SRS needsto be controlled to ensure that the SRS is received correctly.

Parameter settings of other approaches SRS power control solutiondepends on some parameters related to physical uplink shared channel(PUSCH) power control, while the UE cannot obtain the parameters relatedto PUSCH power control on the switched-to carrier used for SRStransmission. As a result, SRS power control is not possible, and theSRS cannot be received correctly.

SUMMARY

Embodiments of the present disclosure provide a power control method andapparatus such that an SRS is transmitted at optimal transmit power on aswitched-to carrier, ensuring that the SRS is received correctly.

According to a first aspect, an embodiment of the present disclosureprovides a power control method, including obtaining a power controlparameter for a SRS, where the power control parameter for the SRSincludes at least one of a target power parameter value for the SRS, apath loss compensation factor, and a closed-loop power control parametervalue for the SRS, and determining transmit power for the SRS on a firstcarrier based on the power control parameter for the SRS. UE cancalculate the transmit power for the SRS on the first carrier based on anewly configured power control parameter for the SRS such that the SRSis transmitted at optimal transmit power on a switched-to carrier,ensuring that the SRS is received correctly.

In a possible design, the first carrier is a carrier on which no PUSCHis sent.

In a possible design, the obtaining a power control parameter for a SRSincludes receiving power control signaling or cross-carrier powercontrol signaling sent by a base station.

In a possible design, the power control signaling includes open-looppower control signaling and/or closed-loop power control signaling.

In a possible design, the obtaining a power control parameter for a SRSincludes obtaining the power control parameter for the SRS from thepower control signaling or the cross-carrier power control signaling.

In a possible design, the power control signaling or the cross-carrierpower control signaling includes Radio Resource Control (RRC) signallingor physical layer signalling.

With the foregoing possible designs, the UE can obtain the power controlparameter for the SRS in different manners. The manner of obtaining thepower control parameter for the SRS is flexible and features ease ofoperation.

In a possible design, the target power parameter value for the SRS is aparameter value obtained based on a preamble initial received targetpower value, or the target power parameter value for the SRS is aparameter value obtained based on the preamble initial received targetpower value and a power adjustment value.

In a possible design, the obtaining the power control parameter from thepower control signaling or the cross-carrier power control signalingincludes parsing out the power control parameter for the SRS from thepower control signaling or the cross-carrier power control signalingbased on a first radio network temporary identifier (RNTI).

In a possible design, the determining transmit power for the SRS basedon the power control parameter for the SRS includes obtaining thetransmit power for the SRS based on at least one of maximum transmitpower of UE, a transmit power adjustment value for the SRS, transmissionbandwidth for the SRS, the target power parameter value for the SRS, thepath loss compensation factor, and an estimated downlink path lossvalue.

In a possible design, the determining transmit power for the SRS basedon the power control parameter for the SRS includes calculating thetransmit power P_(SRS,c1)(i) for the SRS according to a formulaP_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)}, where P_(CMAX,c1)(i) is maximumtransmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, where j equals 0, 1, or 2, α_(SRS,c1)(j) is the path losscompensation factor, and PL_(SRS,c1) is the estimated downlink path lossvalue.

With the foregoing possible implementations, the UE can calculate thetransmit power for the SRS accurately in order to ensure SRStransmission quality.

In a possible design, before the determining transmit power for the SRSbased on the power control parameter for the SRS, the method furtherincludes determining whether the SRS is configured periodically orconfigured aperiodically.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, theclosed-loop power control parameter value for the SRS is an absolutevalue or a relative adjustment value.

In a possible design, before the obtaining the power control parameterfor the SRS, the method further includes obtaining transmission powercontrol (TPC) information, where the TPC information is informationscrambled with the first RNTI.

In a possible design, the obtaining the power control parameter for theSRS includes parsing out the closed-loop power control parameter valuefor the SRS from the TPC information based on the first RNTI.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS,before the obtaining the power control parameter for the SRS, the methodfurther includes obtaining downlink control information (DCI).

In a possible design, the obtaining the power control parameter for theSRS includes obtaining the closed-loop power control parameter value forthe SRS based on the DCI.

In a possible design, if the DCI is control information obtained on asecond carrier, the DCI includes at least a first carrier index.

In a possible design, the second carrier is a switching-from carrier orany carrier other than a switched-to carrier, and the first carrier isthe switched-to carrier.

In a possible design, the obtaining the closed-loop power controlparameter value for the SRS based on the DCI includes obtaining theclosed-loop power control parameter value for the SRS on a carriercorresponding to the first carrier index.

In a possible design, if the DCI is control information obtained on thefirst carrier, the obtaining the closed-loop power control parametervalue for the SRS based on the DCI includes obtaining the closed-looppower control parameter value for the SRS from the DCI.

With the foregoing possible designs, the UE can obtain the closed-looppower control parameter value for the SRS in different manners. Inaddition, a new DCI format is defined such that the UE can obtain acomplete power control parameter for the SRS, to ensure SRS transmissionreliability.

In a possible design, if the closed-loop power control parameter valuefor the SRS is a relative adjustment value, the method further includesdetermining the closed-loop power control parameter value for the SRSbased on at least one of closed-loop power control information or arelative adjustment value for an SRS in a previous subframe.

In a possible design, the determining the closed-loop power controlparameter value for the SRS based on at least one of closed-loop powercontrol information or a relative adjustment value for an SRS in aprevious subframe includes calculating the closed-loop power controlparameter value f_(SRS,c1)(i) for the SRS according to a formulaf_(SRS,c1)(i)=f_(SRS,c1)(i−1)+δ_(SRS,c1)(i−K_(SRS)), wheref_(SRS,c1)(i−1) is the closed-loop power control information for the SRSin the previous subframe, δ_(SRS,c1)(i−K_(SRS)) is the relativeadjustment value, and if the SRS is configured periodically, K^(SRS) isa subframe periodicity of the SRS, or if the SRS is configuredaperiodically, i−K_(SRS) is a subframe number of the previous subframe.

In a possible design, the determining transmit power for the SRS basedon the power control parameter for the SRS includes obtaining thetransmit power for the SRS based on at least one of maximum transmitpower of the UE, a transmit power adjustment value for the SRS,transmission bandwidth for the SRS, the target power parameter value forthe SRS, the path loss compensation factor, an estimated downlink pathloss value, and the closed-loop power control parameter for the SRS.

In a possible design, the determining transmit power for the SRS basedon the power control parameter for the SRS includes calculating thetransmit power P_(SRS,c1)(i) for the SRS according to a formulaP_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)⇄f_(SRS,c1)(i)}, whereP_(CMAX,c1)(i) is maximum transmit power of the UE in an i^(th)subframe, P_(SRS) _(_) _(OFFSET,c1)(m) is the transmit power adjustmentvalue for the SRS, where m equals 0 or 1, M_(SRS,c1) is the transmissionbandwidth for the SRS, P_(O) _(_) _(SRS,c1)(j) is the target powerparameter value for the SRS, α_(SRS,c1)(j) is the path loss compensationfactor, PL_(SRS,c1) is the estimated downlink path loss value, andf_(SRS,c1)(i) is the closed-loop power control parameter value for theSRS.

With the foregoing possible designs, the UE can calculate the transmitpower for the SRS in a closed-loop circumstance accurately in order toensure that the SRS can be received correctly in differentcircumstances.

According to a second aspect, an embodiment of the present disclosureprovides a power control method, including obtaining transmit power in asymbol overlapping portion of a first subframe and a second subframe,where the first subframe is a subframe in which a SRS is transmitted ona first carrier, and the second subframe is a subframe in which an SRSor a physical channel is transmitted on a second carrier, and if thetransmit power is greater than maximum transmit power of UE, controllingtransmit power for a to-be-transmitted signal, where theto-be-transmitted signal includes the SRS and/or the physical channel.

In a possible design, before the controlling transmit power for ato-be-transmitted signal, the method further includes determiningwhether the SRS is configured periodically or configured aperiodically.

In a possible design, the controlling transmit power for ato-be-transmitted signal includes controlling the transmit power for theto-be-transmitted signal based on a periodical configuration of the SRS,or controlling the transmit power for the to-be-transmitted signal basedon an aperiodical configuration of the SRS.

In a possible design, if the SRS is configured periodically, thecontrolling transmit power for a to-be-transmitted signal includesdropping the SRS or performing power scaling for the SRS.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUSCH, and the PUSCH does not include uplinkcontrol information (UCI), the controlling transmit power for ato-be-transmitted signal includes dropping the PUSCH or performing powerscaling for the PUSCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUSCH, and the PUSCH includes UCI, the controllingtransmit power for a to-be-transmitted signal includes dropping the SRSor performing power scaling for the SRS.

In a possible design, if the SRS is configured aperiodically, and thephysical channel is a physical uplink control channel (PUCCH), thecontrolling transmit power for a to-be-transmitted signal includesdropping the SRS or performing power scaling for the SRS, or droppingthe PUCCH or performing power scaling for the PUCCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUCCH, and the PUCCH includes a hybrid automaticrepeat request (HARQ), the controlling transmit power for ato-be-transmitted signal includes dropping the SRS or performing powerscaling for the SRS.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUCCH, and the PUCCH includes only channel stateinformation (CSI), the controlling transmit power for ato-be-transmitted signal includes dropping the SRS or performing powerscaling for the SRS, or dropping the PUCCH or performing power scalingfor the PUCCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a packet random access channel (PRACH), and thePRACH is concurrent, the controlling transmit power for ato-be-transmitted signal includes dropping the SRS or performing powerscaling for the SRS.

An implementation principle and a beneficial effect of the power controlmethod provided in this embodiment are similar to those of the firstaspect, and details are not described herein again.

According to a third aspect, an embodiment of the present disclosureprovides a power control method, where the method includes obtaining apower control parameter for a SRS on a first carrier, where the powercontrol parameter for the SRS includes at least one of a target powerparameter value for the SRS, a path loss compensation factor, and aclosed-loop power control parameter value for the SRS, and sending thepower control parameter for the SRS to UE such that the UE determinestransmit power for the SRS on the first carrier based on the powercontrol parameter for the SRS.

In a possible design, the first carrier is a carrier on which no PUSCHis sent.

In a possible design, the sending the power control parameter for theSRS to UE includes sending the power control parameter for the SRS tothe UE using power control signaling or cross-carrier power controlsignaling.

In a possible design, the power control signaling includes open-looppower control signaling and/or closed-loop power control signaling.

In a possible design, the power control signaling or the cross-carrierpower control signaling includes RRC signaling or physical layersignaling.

In a possible design, the target power parameter value for the SRS is aparameter value obtained based on a preamble initial received targetpower value, or the target power parameter value for the SRS is aparameter value obtained based on the preamble initial received targetpower value and a power adjustment value.

In a possible design, the sending the power control parameter for theSRS to the UE using power control signaling or cross-carrier powercontrol signaling includes scrambling the power control parameter forthe SRS based on a first RNTI, to generate the power control signalingor the cross-carrier power control signaling, and sending the powercontrol signaling or the cross-carrier power control signaling to theUE.

In a possible design, the SRS is configured periodically or configuredaperiodically.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, theclosed-loop power control parameter value for the SRS is an absolutevalue or a relative adjustment value.

In a possible design, the method further includes sending TPCinformation to the UE such that the UE parses out the closed-loop powercontrol parameter value for the SRS from the TPC information, where theTPC information is information scrambled with the first RNTI.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter for the SRS, the methodfurther includes sending DCI to the UE such that the UE obtains theclosed-loop power control parameter value for the SRS based on the DCI.

In a possible design, if the DCI is control information obtained on asecond carrier, the DCI includes at least a first carrier index, and theDCI is used to instruct the UE to obtain the closed-loop power controlparameter value for the SRS on a carrier corresponding to the firstcarrier index.

In a possible design, the second carrier is a switching-from carrier orany carrier other than a switched-to carrier, and the first carrier isthe switched-to carrier.

In a possible design, if the DCI is control information obtained on thefirst carrier, the DCI is used to instruct the UE to obtain theclosed-loop power control parameter value for the SRS from the DCI.

An implementation principle and a beneficial effect of the power controlmethod provided in this embodiment are similar to those of the firstaspect, and details are not described herein again.

According to a fourth aspect, an embodiment of the present disclosureprovides a power control apparatus, including an obtaining moduleconfigured to obtain a power control parameter for a SRS, where thepower control parameter for the SRS includes at least one of a targetpower parameter value for the SRS, a path loss compensation factor, anda closed-loop power control parameter value for the SRS, and adetermining module configured to determine transmit power for the SRS ona first carrier based on the power control parameter for the SRS.

In a possible design, the first carrier is a carrier on which no PUSCHis sent.

In a possible design, the obtaining module is configured to receivepower control signaling or cross-carrier power control signaling sent bya base station.

In a possible design, the power control signaling includes open-looppower control signaling and/or closed-loop power control signaling.

In a possible design, the obtaining module is further further configuredto obtain the power control parameter for the SRS from the power controlsignaling or the cross-carrier power control signaling.

In a possible design, the power control signaling or the cross-carrierpower control signaling includes RRC signaling or physical layersignaling.

In a possible design, the target power parameter value for the SRS is aparameter value obtained based on a preamble initial received targetpower value, or the target power parameter value for the SRS is aparameter value obtained based on the preamble initial received targetpower value and a power adjustment value.

In a possible design, that the obtaining module obtains the powercontrol parameter from the power control signaling or the cross-carrierpower control signaling includes the obtaining module parses out thepower control parameter for the SRS from the power control signalling orthe cross-carrier power control signalling based on a first RNTI.

In a possible design, the determining module is configured to obtain thetransmit power for the SRS based on at least one of maximum transmitpower of UE, a transmit power adjustment value for the SRS, transmissionbandwidth for the SRS, the target power parameter value for the SRS, thepath loss compensation factor, and an estimated downlink path lossvalue.

In a possible design, the determining module is further configured tocalculate the transmit power P_(SRS,c1)(i) for the SRS according to aformula P_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)}, where P_(CMAX,c1)(i) is maximumtransmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, where j equals 0, 1, or 2, α_(SRS,c1)(j) is the path losscompensation factor, and PL_(SRS,c1) is the estimated downlink path lossvalue.

In a possible design, the determining module is further configured todetermine whether the SRS is configured periodically or configuredaperiodically.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, theclosed-loop power control parameter value for the SRS is an absolutevalue or a relative adjustment value.

In a possible design, the obtaining module is further configured toobtain TPC information, where the TPC information is informationscrambled with the first RNTI.

In a possible design, that the obtaining module obtains the powercontrol parameter for the SRS includes the obtaining module parses outthe closed-loop power control parameter value for the SRS from the TPCinformation based on the first RNTI.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, theobtaining module is further configured to obtain DCI.

In a possible design, that the obtaining module obtains the powercontrol parameter for the SRS includes the obtaining module obtains theclosed-loop power control parameter value for the SRS based on the DCI.

In a possible design, if the DCI is control information obtained on asecond carrier, the DCI includes at least a first carrier index.

In a possible design, the second carrier is a switching-from carrier orany carrier other than a switched-to carrier, and the first carrier isthe switched-to carrier.

In a possible design, that the obtaining module obtains the closed-looppower control parameter value for the SRS based on the DCI includes theobtaining module obtains the closed-loop power control parameter valuefor the SRS on a carrier corresponding to the first carrier index.

In a possible design, if the DCI is control information obtained on thefirst carrier, that the obtaining module obtains the closed-loop powercontrol parameter value for the SRS based on the DCI includes theobtaining module obtains the closed-loop power control parameter valuefor the SRS from the DCI.

In a possible design, if the closed-loop power control parameter valuefor the SRS is a relative adjustment value, the determining module isfurther configured to determine the closed-loop power control parametervalue for the SRS based on at least one of closed-loop power controlinformation or a relative adjustment value for an SRS in a previoussubframe.

In a possible design, that the determining module determines theclosed-loop power control parameter for the SRS based on at least one ofclosed-loop power control information or a relative adjustment value foran SRS in a previous subframe includes the determining module calculatesthe closed-loop power control parameter value f_(SRS,c1)(i) for the SRSaccording to a formulaf_(SRS,c1)(i)=f_(SRS,c1)(i−1)+δ_(SRS,c1)(i−K_(SRS)), wheref_(SRS,c1)(i−1) is the closed-loop power control information for the SRSin the previous subframe δ_(SRS,c1)(i−K_(SRS)) is the relativeadjustment value, and if the SRS is configured periodically, K_(SRS) isa subframe periodicity of the SRS, or if the SRS is configuredaperiodically, i−K_(SRS) is a subframe number of the previous subframe.

In a possible design, that the determining module determines transmitpower for the SRS based on the power control parameter for the SRSincludes the determining module obtains the transmit power for the SRSbased on at least one of maximum transmit power of the UE, a transmitpower adjustment value for the SRS, transmission bandwidth for the SRS,the target power parameter value for the SRS, the path loss compensationfactor, the estimated downlink path loss value, and a closed-loop powercontrol parameter for the SRS.

In a possible design, that the determining module determines transmitpower for the SRS based on the power control parameter for the SRSincludes the determining module calculates the transmit powerP_(SRS,c1)(i) for the SRS according to a formulaP_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)+f_(SRS,c1)}, where P_(CMAX,c1)(i)is maximum transmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_SRS,c1) (j) is the target power parameter value for theSRS, α_(SRS,c1)(j) is the path loss compensation factor, PL_(SRS,c1) isthe estimated downlink path loss value, and f_(SRS,c1)(i) is theclosed-loop power control parameter value for the SRS.

An implementation principle and a beneficial effect of the power controlapparatus provided in this embodiment are similar to those of the firstaspect, and details are not described herein again.

According to a fifth aspect, an embodiment of the present disclosureprovides a power control apparatus, including an obtaining moduleconfigured to obtain transmit power in a symbol overlapping portion of afirst subframe and a second subframe, where the first subframe is asubframe in which a SRS is transmitted on a first carrier, and thesecond subframe is a subframe in which an SRS or a physical channel istransmitted on a second carrier, and a processing module configured to,if the transmit power is greater than maximum transmit power of UE,control transmit power for a to-be-transmitted signal, where theto-be-transmitted signal includes the SRS and/or the physical channel.

In a possible design, the processing module is further configured todetermine whether the SRS is configured periodically or configuredaperiodically.

In a possible design, that the processing module controls transmit powerfor a to-be-transmitted signal includes the processing module controlsthe transmit power for the to-be-transmitted signal based on aperiodical configuration of the SRS, or the processing module controlsthe transmit power for the to-be-transmitted signal based on anaperiodical configuration of the SRS.

In a possible design, if the SRS is configured periodically, that theprocessing module controls transmit power for a to-be-transmitted signalincludes the processing module drops the SRS or performs power scalingfor the SRS.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUSCH, and the PUSCH does not include UCI, thatthe processing module controls transmit power for a to-be-transmittedsignal includes the processing module drops the PUSCH or performs powerscaling for the PUSCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUSCH, and the PUSCH includes UCI, that theprocessing module controls transmit power for a to-be-transmitted signalincludes the processing module drops the SRS or performs power scalingfor the SRS.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUCCH, that the processing module controlstransmit power for a to-be-transmitted signal includes the processingmodule drops the SRS or performs power scaling for the SRS, or theprocessing module drops the PUCCH or performs power scaling for thePUCCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUCCH, and the PUCCH includes a HARQ, that theprocessing module controls transmit power for a to-be-transmitted signalincludes the processing module drops the SRS or performs power scalingfor the SRS.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PUCCH, and the PUCCH includes only CSI, that theprocessing module controls transmit power for a to-be-transmitted signalincludes the processing module drops the SRS or performs power scalingfor the SRS, or the processing module drops the PUCCH or performs powerscaling for the PUCCH.

In a possible design, if the SRS is configured aperiodically, thephysical channel is a PRACH, and the PRACH is concurrent, that theprocessing module controls transmit power for a to-be-transmitted signalincludes the processing module drops the SRS or performs power scalingfor the SRS.

An implementation principle and a beneficial effect of the power controlapparatus provided in this embodiment are similar to those of the firstaspect, and details are not described herein again.

According to a sixth aspect, an embodiment of the present disclosureprovides a power control apparatus, including an obtaining moduleconfigured to obtain a power control parameter for a SRS on a firstcarrier, where the power control parameter for the SRS includes at leastone of a target power parameter value for the SRS, a path losscompensation factor, and a closed-loop power control parameter value forthe SRS, and a sending module configured to send the power controlparameter for the SRS to UE such that the UE determines transmit powerfor the SRS on the first carrier based on the power control parameterfor the SRS.

In a possible design, the first carrier is a carrier on which no PUSCHis sent.

In a possible design, the sending module is further configured to sendthe power control parameter for the SRS to the UE using power controlsignaling or cross-carrier power control signaling.

In a possible design, the power control signaling includes open-looppower control signaling and/or closed-loop power control signaling.

In a possible design, the power control signaling or the cross-carrierpower control signaling includes RRC signaling or physical layersignaling.

In a possible design, the target power parameter value for the SRS is aparameter value obtained based on a preamble initial received targetpower value, or the target power parameter value for the SRS is aparameter value obtained based on the preamble initial received targetpower value and a power adjustment value.

In a possible design, that the sending module sends the power controlparameter for the SRS to the UE using power control signaling orcross-carrier power control signaling includes the sending modulescrambles the power control parameter for the SRS based on a first RNTI,to generate the power control signaling or the cross-carrier powercontrol signaling, and sends the power control signaling or thecross-carrier power control signaling to the UE.

In a possible design, the SRS is configured periodically or configuredaperiodically.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, theclosed-loop power control parameter value for the SRS is an absolutevalue or a relative adjustment value.

In a possible design, the sending module is further configured to sendTPC information to the UE such that the UE parses out the closed-looppower control parameter value for the SRS from the TPC information,where the TPC information is information scrambled with the first RNTI.

In a possible design, if the power control parameter for the SRSincludes the closed-loop power control parameter value for the SRS, thesending module is further configured to send DCI to the UE such that theUE obtains the closed-loop power control parameter value for the SRSbased on the DCI.

In a possible design, if the DCI is control information obtained on asecond carrier, the DCI includes at least a first carrier index, and theDCI is used to instruct the UE to obtain the closed-loop power controlparameter value for the SRS on a carrier corresponding to the firstcarrier index.

In a possible design, the second carrier is a switching-from carrier orany carrier other than a switched-to carrier, and the first carrier isthe switched-to carrier.

In a possible design, if the DCI is control information obtained on thefirst carrier, the DCI is used to instruct the UE to obtain theclosed-loop power control parameter value for the SRS from the DCI.

An implementation principle and a beneficial effect of the power controlapparatus provided in this embodiment are similar to those of the firstaspect, and details are not described herein again.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure or in the prior art more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments or other approaches. Apparently, the accompanying drawingsin the following description show some embodiments of the presentdisclosure, and persons of ordinary skill in the art may still deriveother drawings from these accompanying drawings without creativeefforts.

FIG. 1 is a schematic diagram of an application scenario of a powercontrol method according to an embodiment of the present disclosure.

FIG. 2 is a flowchart of a power control method according to Embodiment1 of the present disclosure.

FIG. 3 is a flowchart of a power control method according to Embodiment2 of the present disclosure.

FIG. 4 is a flowchart of a power control method according to Embodiment3 of the present disclosure.

FIG. 5 is a flowchart of a power control method according to Embodiment4 of the present disclosure.

FIG. 6 is a structural diagram of a power control apparatus according toEmbodiment 5 of the present disclosure.

FIG. 7 is a structural diagram of a power control apparatus according toEmbodiment 6 of the present disclosure.

FIG. 8 is a structural diagram of a power control apparatus according toEmbodiment 7 of the present disclosure.

FIG. 9 is a structural diagram of UE according to Embodiment 8 of thepresent disclosure.

FIG. 10 is a structural diagram of a base station according toEmbodiment 9 of the present disclosure.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic diagram of an application scenario of a powercontrol method according to an embodiment of the present disclosure. Themethod is applied to a wireless communications system, for example, anLTE-A system. As shown in FIG. 1, the scenario includes a network device1, a user terminal 2, and a user terminal 3. The power control methodprovided in this application is mainly used for data transmissionbetween the network device and the user terminal. It should be notedthat the scenario may further include other network devices and otheruser terminals. FIG. 1 is merely an example for description and imposesno limitation.

The user terminal used in this embodiment of the present disclosure maybe a device that provides voice and/or data connectivity for a user, ahandheld device with a wireless connection function, or anotherprocessing device connected to a wireless modem. A wireless terminal maycommunicate with one or more core networks through a radio accessnetwork. The wireless terminal may be a mobile terminal, such as amobile phone (also referred to as a “cellular” phone) or a computerprovided with a mobile terminal, and for example, may be a portablemobile apparatus, a pocket-sized mobile apparatus, a handheld mobileapparatus, a computer built-in mobile apparatus, or an in-vehicle mobileapparatus, which exchanges voice and/or data with the radio accessnetwork.

The network device used in this embodiment of the present disclosure maybe a base station, an access point, or a device in communication with awireless terminal via one or more sectors at an over-the-air interfacein an access network. The base station may be configured to convert areceived over-the-air frame to an internet protocol (IP) packet andconvert a received IP packet to an over-the-air frame, and serve as arouter between the wireless terminal and a rest portion of the accessnetwork, where the rest portion of the access network may include an IPnetwork. The base station may coordinate attribute management of the airinterface. For example, the base station may be a base station in globalsystem for mobile (GSM) or code division multiple access (CDMA), may bea base station in wideband CDMA (WCDMA), known as a NodeB, or may be anevolved NodeB in LTE. This is not limited in this application.

FIG. 2 is a flowchart of a power control method according to Embodiment1 of the present disclosure, where the method is executed by UE. Asshown in FIG. 2, the method includes the following steps.

Step 101: Obtain a power control parameter for a SRS, where the powercontrol parameter for the SRS includes at least one of a target powerparameter value for the SRS, a path loss compensation factor, and aclosed-loop power control parameter value for the SRS.

In this embodiment, the UE may obtain the power control parameter forthe SRS in different manners. For example, a base station transmits apreconfigured power control parameter for the SRS to the UE using aswitching-from or switched-to carrier for SRS transmission.Alternatively, the base station sends a target power parameter value forthe SRS and a path loss compensation factor to the UE using physicallayer signaling or control signaling, and then indicates a closed-looppower control parameter value for the SRS to the UE using TPCinformation. Alternatively, various values in the power controlparameter for the SRS may be obtained in other manners.

Step 102: Determine transmit power for the SRS on a first carrier basedon the power control parameter for the SRS.

In this embodiment, the first carrier is a switched-to carrier afterSRS-based carrier switching, and also referred to as a non-uplinkcarrier, in order that SRS transmission is performed on the carrier. TheUE may calculate the transmit power for the SRS on the first carrierbased on the power control parameter for the SRS such that the SRS issent on the first carrier at appropriate transmit power.

In the power control method provided in this embodiment, the UE obtainsthe power control parameter for the SRS, where the power controlparameter includes at least one of the target power parameter value forthe SRS, the path loss compensation factor, and the closed-loop powercontrol parameter value for the SRS, and determines the transmit powerfor the SRS on the first carrier based on the power control parameterfor the SRS. The UE can calculate transmit power for the SRS on aswitched-to carrier based on a newly configured power control parameterfor the SRS such that the SRS is transmitted at optimal transmit poweron a switched-to carrier, ensuring that the SRS is received correctly.

Optionally, in the embodiment shown in FIG. 2, the first carrier is acarrier on which no PUSCH is sent. That is, the first carrier is usedfor SRS sending, but not for PUSCH sending.

FIG. 3 is a flowchart of a power control method according to Embodiment2 of the present disclosure, and the method shown in FIG. 3 is aspecific implementation process of step 101. As shown in FIG. 3, themethod includes the following steps.

Step 201: Receive power control signaling or cross-carrier power controlsignaling sent by a base station, where the power control signalingincludes open-loop power control signaling and/or closed-loop powercontrol signaling.

In this embodiment, the base station may deliver the power controlsignaling to UE using power control signaling on a switched-to carrierto UE, or may indicate the power control signaling to the UE using thecross-carrier power control signaling. The cross-carrier power controlsignaling includes signaling that is received on a switching-fromcarrier on which the SRS is located or any carrier other than theswitched-to carrier, and that is used for notification about relatedpower configuration for SRS transmission on the switched-to carrierafter SRS-based carrier switching. In other words, the cross-carrierpower control signaling is signaling sent by the base station on aswitching-from carrier or any carrier other than the switched-tocarrier, and the signaling includes the power control parameter for theSRS on the switched-to carrier. The open-loop power control signalingmay include the target power parameter value for the SRS and the pathloss compensation factor. The closed-loop power control signaling mayinclude the target power parameter value for the SRS, the path losscompensation factor, and the closed-loop power control parameter valuefor the SRS.

Optionally, the power control signaling or the cross-carrier powercontrol signaling includes RRC signaling or physical layer signaling.

Step 202: Obtain the power control parameter for the SRS from the powercontrol signaling or the cross-carrier power control signaling.

In this embodiment, after the UE receives the power control signaling orthe cross-carrier power control signaling delivered by the base station,the UE parses the power control signaling or the cross-carrier powercontrol signaling, to obtain the power control parameter for the SRS.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

In this embodiment, the base station may send the preamble initialreceived target power value to the UE using the power control signalingor the cross-carrier power control signaling, and the UE calculates thetarget power parameter value for the SRS based on the preamble initialreceived target power value. Alternatively, the base station maycalculate the target power parameter value for the SRS by adding thepreamble initial received target power value and the power adjustmentvalue, and then send the calculated target power parameter value for theSRS to the UE using the power control signaling or the cross-carrierpower control signaling. The power adjustment value may alternatively beobtained from a response message of a specially defined random accesschannel (RACH). The power adjustment value is also referred to as apower offset or a power offset.

Further, the obtaining the power control parameter from the powercontrol signaling or the cross-carrier control signaling includesparsing out the power control parameter for the SRS from the powercontrol signaling or the cross-carrier power control signaling based ona first RNTI.

In this embodiment, the first RNTI is different from the TPC-RNTI ofother approaches. The first RNTI is an RNTI that is redefined in thisapplication, and the first RNTI may be named TPC-SRS-RNTI. The firstRNTI is used to scramble or mask the power control parameter for theSRS, and the scrambled parameter is carried in the physical layersignaling for indication to the UE.

In the power control method provided in this embodiment, the UE receivesthe power control signaling or the cross-carrier power control signalingsent by the base station, and obtains the power control parameter forthe SRS from the power control signaling or the cross-carrier powercontrol signaling. The base station may indicate the power controlparameter for the SRS to the UE using RRC signaling, medium accesscontrol (MAC) signaling, or physical layer signaling, and may furtherscramble the power control parameter for the SRS using the newly definedRNTI. The base station indicates the power control parameter for the SRSto the UE in different manners. The method is flexible, and featuresease of operation.

Optionally, the determining transmit power for the SRS based on thepower control parameter for the SRS includes obtaining the transmitpower for the SRS based on at least one of maximum transmit power of theUE, a transmit power adjustment value for the SRS, transmissionbandwidth for the SRS, the target power parameter value for the SRS, thepath loss compensation factor, and an estimated downlink path lossvalue.

Specifically, in an open-loop case, the determining transmit power forthe SRS based on the power control parameter for the SRS includescalculating the transmit power P_(SRS,c1)(i) for the SRS according to aformula P_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(c1)}, where P_(CMAX,c1)(i) is maximumtransmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, where j equals 0, 1, or 2, α_(SRS,c1)(j) is the path losscompensation factor, and PL_(c1) is the estimated downlink path lossvalue. α_(SRS,c1)(j) may be fixed to 1, and for P_(O) _(_) _(SRS,c1)(j),usually j equals 2. When j equals 0, P_(O) _(_) _(SRS,c1)(j) is asemi-persistent scheduling transmit power, when j equals 1, P_(O) _(_)_(SRS,c1)(j) is a dynamic scheduling transmit power, and when j equals2, P_(O) _(_) _(SRS,c1)(j) is a random access scheduling transmit power.

Further, before the determining transmit power for the SRS based on thepower control parameter for the SRS, the method further includesdetermining whether the SRS is configured periodically or configuredaperiodically.

In this embodiment, the UE may determine whether the SRS is configuredperiodically or configured aperiodically, and then determine thetransmit power for the SRS based on a periodical configurationcharacteristic of the SRS and the power control parameter for the SRS,to ensure that the SRS can be received correctly in variouscircumstances.

Optionally, in a closed-loop circumstance, if the power controlparameter for the SRS includes the closed-loop power control parametervalue for the SRS, the closed-loop power control parameter value for theSRS is an absolute value or a relative adjustment value.

In this embodiment, if the closed-loop power control parameter value forthe SRS is an absolute value, the absolute value may be directly used tocalculate the transmit power for the SRS, if the closed-loop powercontrol parameter value for the SRS is a relative adjustment value, theclosed-loop power control parameter value for the SRS needs to becalculated first based on the relative adjustment value, and then theclosed-loop power control parameter value for the SRS obtained throughcalculation is used to calculate the transmit power for the SRS.

Optionally, if the closed-loop power control parameter value for the SRSis a relative adjustment value, the method further includes determiningthe closed-loop power control parameter value for the SRS based on atleast one of closed-loop power control information or a relativeadjustment value for an SRS in a previous subframe.

Specifically, the determining the closed-loop power control parametervalue for the SRS based on at least one of closed-loop power controlinformation or a relative adjustment value for an SRS in a previoussubframe includes calculating the closed-loop power control parametervalue f_(c1)(i) for the SRS according to a formulaf_(c1)(i)=f_(c1)(i−)+δ_(SRS,c1)(i−K_(SRS)), where f_(c1)(i−1) is theclosed-loop power control information for the SRS in the previoussubframe, δ_(SRS,c1)(i−K_(SRS)) is the relative adjustment value, and ifthe SRS is configured periodically, K_(SRS) is a subframe periodicity ofthe SRS, or if the SRS is configured aperiodically, i−K_(SRS) is asubframe number of the previous subframe.

Further, the determining transmit power for the SRS based on the powercontrol parameter for the SRS includes obtaining the transmit power forthe SRS based on at least one of maximum transmit power of the UE, atransmit power adjustment value for the SRS, transmission bandwidth forthe SRS, the target power parameter value for the SRS, the path losscompensation factor, an estimated downlink path loss value, and theclosed-loop power control parameter for the SRS.

Specifically, the determining transmit power for the SRS based on thepower control parameter for the SRS includes calculating the transmitpower P_(SRS,c1)(i) for the SRS according to a formulaP_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(c1)+f_(SRS,c1)(i)}, where P_(CMAX,c1)(i)is maximum transmit power of the UE in an i^(th) subframe on aswitched-to carrier C1, P_(SRS) _(_) _(OFFSET,c1)(m) is the transmitpower adjustment value for the SRS, where m equals 0 or 1, M_(SRS,c1) isthe transmission bandwidth for the SRS, P_(O) _(_) _(SRS,c1)(j) is thetarget power parameter value for the SRS, α_(SRS,c1)(j) is the path losscompensation factor, PL_(c1) is the estimated downlink path loss value,and f_(c1)(i) is the closed-loop power control parameter value for theSRS. α_(SRS,c1)(j) may be fixed to 1, and for P_(O) _(_) _(STS,c1)(j),usually j equals 2. When j equals 0, P_(O) _(_) _(SRS,c1)(j) is asemi-persistent scheduling transmit power, when j equals 1, P_(O) _(_)_(SRS,c1)(j) is a dynamic scheduling transmit power, and when j equals2, P_(O) _(_) _(SRS,c1)(j) is a random access scheduling transmit power.

Further, before the obtaining the power control parameter for the SRS,the method further includes obtaining TPC information, where the TPCinformation is information scrambled or masked with the first RNTI.

Still further, the obtaining the power control parameter for the SRSincludes parsing out the closed-loop power control parameter value forthe SRS from the TPC information based on the first RNTI.

In this embodiment, the closed-loop power control parameter value forthe SRS may be included in the TPC information scrambled with the firstRNTI, and the first RNTI is indicated to the UE in advance. The UE maydescramble the TPC information based on the first RNTI, to obtain theclosed-loop power control parameter value for the SRS.

Still further, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, before theobtaining the power control parameter for the SRS, the method furtherincludes obtaining Downlink DCI.

Still further, the obtaining the power control parameter for the SRSincludes obtaining the closed-loop power control parameter value for theSRS based on the DCI.

In this embodiment, different formats of DCI may be defined as follows.

A first DCI format, if the DCI is control information obtained on asecond carrier, the DCI includes at least a first carrier index, wherethe second carrier is a switching-from carrier or any carrier other thana switched-to carrier, and the first carrier is the switched-to carrier.

Correspondingly, in this embodiment, the obtaining the closed-loop powercontrol parameter value for the SRS based on the DCI includes obtainingthe closed-loop power control parameter value for the SRS on a carriercorresponding to the first carrier index.

In this embodiment, in the case of cross-carrier notification, DCIobtained on a switching-from carrier needs to include at least an indexof a switched-to carrier such that the UE obtains, based on the firstcarrier index, the closed-loop power control parameter value for the SRSon a carrier corresponding to the carrier index.

A second DCI format, if the DCI is control information obtained on thefirst carrier, the obtaining the closed-loop power control parametervalue for the SRS based on the DCI includes obtaining the closed-looppower control parameter value for the SRS from the DCI.

In this embodiment, when the DCI is control information obtained on aswitched-to carrier, the closed-loop power control parameter value forthe SRS in the new DCI format is used directly to perform SRS TPC.

FIG. 4 is a flowchart of a power control method according to Embodiment3 of the present disclosure. The method relates to how power control isperformed when SRS-based carrier switching is triggered, if symbols oftwo subframes overlap and transmit power in an overlapping portionexceeds maximum transmit power of UE. As shown in FIG. 4, the methodincludes the following steps.

Step 301: Obtain transmit power in a symbol overlapping portion of afirst subframe and a second subframe, where the first subframe is asubframe in which a SRS is transmitted on a first carrier, and thesecond subframe is a subframe in which an SRS or a physical channel istransmitted on a second carrier.

In this embodiment, if a symbol of a subframe in which the SRS istransmitted on the first carrier overlaps a symbol of a subframe inwhich the SRS or the physical channel is transmitted on the secondcarrier, the transmit power in the symbol overlapping portion needs tobe calculated. For example, when a plurality of timing advance groups(TAG) are configured for UE, when a symbol in subframe i for SRStransmission of the UE on one assumed serving carrier/cell in one TAGoverlaps a symbol in a subframe i or a subframe i+1 used for PUCCHtransmission on another serving carrier/cell, transmit power in thesymbol overlapping portion is calculated.

Step 302: If the transmit power is greater than maximum transmit powerof UE, control transmit power for a to-be-transmitted signal, where theto-be-transmitted signal includes the SRS and/or the physical channel.

In this embodiment, if the transmit power is greater than the maximumtransmit power of the UE, the transmit power for the to-be-transmittedsignal is controlled. For example, if the transmit power is greater thanthe maximum transmit power of the UE, a portion of the to-be-transmittedsignal is appropriately dropped, or power scaling is performed on theto-be-transmitted signal.

In the power control method provided in this embodiment, the UE obtainsthe transmit power in the symbol overlapping portion of the firstsubframe in which the SRS is transmitted on the first carrier and thesecond subframe in which the SRS or the physical channel is transmittedon the second carrier, and if the transmit power is greater than themaximum transmit power of the UE, controls the transmit power for theto-be-transmitted signal such that the to-be-transmitted signal istransmitted at appropriate power, ensuring transmission efficiency ofthe to-be-transmitted signal.

Optionally, before the controlling transmit power for ato-be-transmitted signal, the method further includes determiningwhether the SRS is configured periodically or configured aperiodically.

Further, the controlling transmit power for a to-be-transmitted signalincludes controlling the transmit power for the to-be-transmitted signalbased on a periodical configuration of the SRS, or controlling thetransmit power for the to-be-transmitted signal based on an aperiodicalconfiguration of the SRS.

In this embodiment, dropping a portion of the to-be-transmitted signalor performing power scaling for a portion of the to-be-transmittedsignal may be selected based on a periodical characteristic of the SRS.

Optionally, if the SRS is configured periodically, the controllingtransmit power for a to-be-transmitted signal includes dropping the SRSor performing power scaling for the SRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH does not include UCI, the controlling transmitpower for a to-be-transmitted signal includes dropping the PUSCH orperforming power scaling for the PUSCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH includes UCI, the controlling transmit powerfor a to-be-transmitted signal includes dropping the SRS or performingpower scaling for the SRS.

Optionally, if the SRS is configured aperiodically, and the physicalchannel is a PUCCH, the controlling transmit power for ato-be-transmitted signal includes dropping the SRS or performing powerscaling for the SRS, or dropping the PUCCH or performing power scalingfor the PUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes a HARQ, the controlling transmitpower for a to-be-transmitted signal includes dropping the SRS orperforming power scaling for the SRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes only CSI, the controlling transmitpower for a to-be-transmitted signal includes dropping the SRS orperforming power scaling for the SRS, or dropping the PUCCH orperforming power scaling for the PUCCH.

In this embodiment, when the SRS is configured aperiodically, thephysical channel is a PUCCH, the PUCCH includes only CSI, and the PUCCHdoes not include a HARQ, the controlling transmit power for ato-be-transmitted signal includes dropping the SRS or performing powerscaling for the SRS, or dropping the PUCCH or performing power scalingfor the PUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PRACH, and the PRACH is concurrent, the controlling transmit powerfor a to-be-transmitted signal includes dropping the SRS or performingpower scaling for the SRS.

The following describes the method of “controlling the transmit powerfor the to-be-transmitted signal based on a periodical characteristic ofthe SRS” in detail based on different UE configurations.

Case 1:

When a plurality of TAGs are configured for the UE, when a symbol in asubframe i used for SRS transmission of the UE on one assumed servingcarrier/cell in one TAG overlaps a symbol in a subframe i or a subframei+1 used for PUCCH/PUSCH transmission on another serving carrier/cell,if the transmit power in the symbol overlapping portion exceeds themaximum transmit power of the UE, the following cases apply.

(1) When the SRS is configured periodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, the UEdrops SRS transmission or performs power scaling for SRS transmission.

(2) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, only aPUSCH is present, and the PUSCH does not include UCI, the UE drops PUSCHtransmission or performs power scaling for PUSCH transmission, or the UEdrops SRS transmission or performs power scaling for SRS transmission.

(3) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, only aPUSCH is present, and the PUSCH includes UCI, the UE drops SRStransmission or performs power scaling for SRS transmission.

(4) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, and aPUCCH is present, the UE drops SRS transmission or performs powerscaling for SRS transmission, or the UE drops PUSCH transmission orperforms power scaling for PUSCH transmission.

(5) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, a PUCCHis present, and the PUCCH includes a HARQ, the UE drops SRS transmissionor performs power scaling for SRS transmission.

(6) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, a PUCCHis present, and the PUCCH includes only CSI, the UE drops SRStransmission or the PUCCH, or the UE performs power scaling for SRStransmission or performs power scaling for the PUCCH.

Case 2:

When a plurality of TAGs and more than two serving carriers/cells areconfigured for the UE, when a symbol in a subframe i used for SRStransmission on one serving carrier/cell overlaps a symbol in a subframei used for SRS transmission on another serving carrier/cell, and/oroverlaps a symbol in a subframe i or a subframe i+1 used for PUCCH/PUSCHtransmission on another serving carrier/cell, if transmit power for thesymbol overlapping portion exceeds the maximum transmit power of the UE,the following cases apply.

(1) When the SRS is configured periodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, the UEdrops SRS transmission or performs power scaling for SRS transmission.

(2) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, only aPUSCH is present, and the PUSCH does not include UCI, the UE drops PUSCHtransmission or performs power scaling for PUSCH transmission, or the UEdrops SRS transmission or performs power scaling for SRS transmission.

(3) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, only aPUSCH is present, and the PUSCH includes UCI, the UE drops SRStransmission or performs power scaling for SRS transmission.

(4) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, and aPUCCH is present, the UE drops SRS transmission or performs powerscaling for SRS transmission, or the UE drops PUSCH transmission orperforms power scaling for PUSCH transmission.

(5) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, a PUCCHis present, and the PUCCH includes HARQ, the UE drops SRS transmissionor performs power scaling for SRS transmission.

(6) When the SRS is configured aperiodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, a PUCCHis present, and the PUCCH includes only CSI, the UE drops SRStransmission or the PUCCH, or the UE performs power scaling for SRStransmission or performs power scaling for the PUCCH.

Case 3:

When a plurality of TAGs are configured for the UE, the UE transmits aPRACH on a secondary serving carrier/cell, and the PRACH is concurrentin a symbol in a subframe used for SRS transmission on a differentserving carrier/cell, if the transmit power in the symbol overlappingportion exceeds the maximum transmit power of the UE, the followingcases apply.

(1) When the SRS is configured periodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, the UEdrops SRS transmission or performs power scaling for SRS transmission.

(2) When the SRS is configured periodically, if transmit power in anyoverlapping symbol exceeds the maximum transmit power of the UE, and aPRACH is concurrent, the UE drops SRS transmission or performs powerscaling for SRS transmission.

FIG. 5 is a flowchart of a power control method according to Embodiment4 of the present disclosure. The method is executed by a base station.As shown in FIG. 5, the method includes the following steps.

Step 401: Obtain a power control parameter for a SRS on a first carrier,where the power control parameter for the SRS includes at least one of atarget power parameter value for the SRS, a path loss compensationfactor, and a closed-loop power control parameter value for the SRS.

In this embodiment, the power control parameter for the SRS is speciallyconfigured, in order to calculate transmit power for the SRS on aswitched-to carrier.

Step 402: Send the power control parameter for the SRS to UE such thatthe UE determines transmit power for the SRS on the first carrier basedon the power control parameter for the SRS.

In this embodiment, the base station may send the power controlparameter for the SRS in different manners. For example, the basestation transmits a preconfigured power control parameter for the SRS tothe UE using a switched-to carrier for SRS transmission. Alternatively,the base station sends a target power parameter value for the SRS and apath loss compensation factor to the UE using physical layer signalingor control signaling, and then indicates a closed-loop power controlparameter value for the SRS to the UE using TPC information.Alternatively, the base station sends various values in the powercontrol parameter for the SRS to the UE in other manners. The UE maycalculate the transmit power for the SRS on the first carrier based onthe power control parameter for the SRS such that the SRS is sent on thefirst carrier at appropriate transmit power.

In the power control method provided in this embodiment, the basestation obtains the power control parameter for the SRS on the firstcarrier, where the power control parameter includes at least one of thetarget power parameter value for the SRS, the path loss compensationfactor, and the closed-loop power control parameter value for the SRS,sends the power control parameter for the SRS to the UE such that the UEdetermines the transmit power for the SRS on the first carrier based onthe power control parameter for the SRS. In this way, the UE cancalculate transmit power for the SRS on a switched-to carrier based on anewly configured power control parameter for the SRS such that the SRSis transmitted on the switched-to carrier at optimal transmit power,ensuring that the SRS is received correctly.

Optionally, the first carrier is a carrier on which no PUSCH is sent.

Optionally, the sending the power control parameter for the SRS to UEincludes sending the power control parameter for the SRS to the UE usingpower control signaling or cross-carrier power control signaling.

The power control signaling includes open-loop power control signalingand/or closed-loop power control signaling.

The power control signaling or the cross-carrier power control signalingincludes RRC signaling or physical layer signaling.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

Further, the sending the power control parameter for the SRS to the UEusing power control signaling or cross-carrier power control signalingincludes scrambling the power control parameter for the SRS based on afirst RNTI, to generate the power control signaling or the cross-carrierpower control signaling, and sending the power control signaling or thecross-carrier power control signaling to the UE.

Optionally, the SRS is configured periodically or configuredaperiodically.

Further, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the closed-looppower control parameter value for the SRS is an absolute value or arelative adjustment value.

Still further, the method further includes sending TPC information tothe UE such that the UE parses out the closed-loop power controlparameter value for the SRS from the TPC information, where the TPCinformation is information scrambled with the first RNTI.

Still further, if the power control parameter for the SRS includes theclosed-loop power control parameter for the SRS, the method furtherincludes sending DCI to the UE such that the UE obtains the closed-looppower control parameter value for the SRS based on the DCI.

Optionally, if the DCI is control information obtained on a secondcarrier, the DCI includes at least a first carrier index, and the DCI isused to instruct the UE to obtain the closed-loop power controlparameter value for the SRS on a carrier corresponding to the firstcarrier index.

The second carrier is a switching-from carrier or any carrier other thana switched-to carrier, and the first carrier is the switched-to carrier.

Optionally, if the DCI is control information obtained on the firstcarrier, the DCI is used to instruct the UE to obtain the closed-looppower control parameter value for the SRS from the DCI.

The power control method provided in this embodiment is implemented by abase station and corresponds to the UE-side power control method. Fordetailed descriptions about an implementation principle and specifictechnical features of the method, refer to the UE-side power controlmethod in the embodiments in FIG. 2 to FIG. 4. Details are not describedherein again.

FIG. 6 is a structural diagram of a power control apparatus according toEmbodiment 5 of the present disclosure. As shown in FIG. 6, theapparatus includes an obtaining module 11 and a determining module 12.The obtaining module 11 is configured to obtain a power controlparameter for a SRS, where the power control parameter for the SRSincludes at least one of a target power parameter value for the SRS, apath loss compensation factor, and a closed-loop power control parametervalue for the SRS. The determining module 12 is configured to determinetransmit power for the SRS on a first carrier based on the power controlparameter for the SRS.

The apparatus in this embodiment may be configured to execute thetechnical solution of the method embodiment shown in FIG. 2. Theirimplementation principles and technical effects are similar, and no moredetails are provided herein.

Optionally, the first carrier is a carrier on which no PUSCH is sent.

Optionally, the obtaining module 11 is further configured to obtainpower control signaling or cross-carrier power control signaling sent bya base station.

Optionally, the power control signaling includes open-loop power controlsignaling and/or closed-loop power control signaling.

Optionally, the obtaining module 11 is further configured to obtain thepower control parameter for the SRS from the power control signaling orthe cross-carrier power control signaling.

Optionally, the power control signaling or the cross-carrier powercontrol signaling includes RRC signaling or physical layer signaling.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

Optionally, that the obtaining module 11 obtains the power controlparameter from the power control signaling or the cross-carrier powercontrol signaling includes that the obtaining module 11 parses out thepower control parameter for the SRS from the power control signaling orthe cross-carrier power control signaling based on a first RNTI.

Optionally, the determining module 12 is configured to obtain thetransmit power for the SRS based on at least one of maximum transmitpower of UE, a transmit power adjustment value for the SRS, transmissionbandwidth for the SRS, the target power parameter value for the SRS, thepath loss compensation factor, and an estimated downlink path lossvalue.

Optionally, the determining module 12 is further configured to calculatethe transmit power P_(SRS,c1)(i) for the SRS according to a formulaP_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)}, where P_(CMAX,c1)(i) is maximumtransmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, where j equals 0, 1, or 2, α_(SRS,c1)(j) is the path losscompensation factor, and PL_(SRS,c1) is the estimated downlink path lossvalue.

Optionally, the determining module 12 is further configured to determinewhether the SRS is configured periodically or configured aperiodically.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the closed-looppower control parameter value for the SRS is an absolute value or arelative adjustment value.

Optionally, the obtaining module 11 is further configured to obtain TPCinformation, where the TPC information is information scrambled with thefirst RNTI.

Optionally, that the obtaining module 11 obtains the power controlparameter for the SRS includes that the obtaining module 11 parses outthe closed-loop power control parameter value for the SRS from the TPCinformation based on the first RNTI.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the obtainingmodule 11 is further configured to obtain DCI.

Optionally, that the obtaining module 11 obtains the power controlparameter for the SRS includes that the obtaining module 11 obtains theclosed-loop power control parameter value for the SRS based on the DCI.

Optionally, if the DCI is control information obtained on a secondcarrier, the DCI includes at least a first carrier index.

Optionally, the second carrier is a switching-from carrier or anycarrier other than a switched-to carrier, and the first carrier is theswitched-to carrier.

Optionally, that the obtaining module 11 obtains the closed-loop powercontrol parameter value for the SRS based on the DCI includes that theobtaining module 11 obtains the closed-loop power control parametervalue for the SRS on a carrier corresponding to the first carrier index.

Optionally, if the DCI is control information obtained on the firstcarrier, that the obtaining module 11 obtains the closed-loop powercontrol parameter value for the SRS based on the DCI includes that theobtaining module 11 obtains the closed-loop power control parametervalue for the SRS from the DCI.

Optionally, if the closed-loop power control parameter value for the SRSis a relative adjustment value, the determining module 12 is furtherconfigured to determine the closed-loop power control parameter valuefor the SRS based on at least one of closed-loop power controlinformation or a relative adjustment value for an SRS in a previoussubframe.

Optionally, that the determining module 12 determines the closed-looppower control parameter for the SRS based on at least one of closed-looppower control information or a relative adjustment value for an SRS in aprevious subframe includes that the determining module 12 calculates theclosed-loop power control parameter value f_(SRS,c1)(i) for the SRSaccording to a formulaf_(SRS,c1)(i)=f_(SRS,c1)(i−)+δ_(SRS,c1)(i−K_(SRS)), wheref_(SRS,c1)(i−1) is the closed-loop power control information for the SRSin the previous subframe, δ_(SRS,c1)(i−K_(SRS)) is the relativeadjustment value, and if the SRS is configured periodically, K_(SRS) isa subframe periodicity of the SRS, or if the SRS is configuredaperiodically, i−K_(SRS) is a subframe number of the previous subframe.

Optionally, that the determining module 12 determines transmit power forthe SRS based on the power control parameter for the SRS includes thatthe determining module 12 obtains the transmit power for the SRS basedon at least one of maximum transmit power of the UE, a transmit poweradjustment value for the SRS, transmission bandwidth for the SRS, thetarget power parameter value for the SRS, the path loss compensationfactor, the estimated downlink path loss value, and a closed-loop powercontrol parameter for the SRS.

Optionally, that the determining module 12 determines transmit power forthe SRS based on the power control parameter for the SRS includes thatthe determining module 12 calculates the transmit power P_(SRS,c1)(i)for the SRS according to a formula P_(SRS,c1)(i)=min{P_(CMAX,c1)(i),P_(SRS) _(_) _(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)+f_(SRS,c1)(i)}, whereP_(CMAX,c1)(i) is maximum transmit power of the UE in an i^(th)subframe, P_(SRS) _(_) _(OFFSET,c1)(m) is the transmit power adjustmentvalue for the SRS, where m equals 0 or 1, M_(SRS,c1) is the transmissionbandwidth for the SRS, P_(O) _(_) _(SRS,c1)(j) is the target powerparameter value for the SRS, α_(SRS,c1)(j) is the path loss compensationfactor, PL_(SRS,c1) is the estimated downlink path loss value, andf_(SRS,c1)(i) is the closed-loop power control parameter value for theSRS.

The apparatus in this embodiment may be configured to execute thetechnical solution of the method embodiment shown in FIG. 2 or FIG. 3.Their implementation principles and technical effects are similar, andno more details are provided herein.

FIG. 7 is a structural diagram of a power control apparatus according toEmbodiment 6 of the present disclosure. As shown in FIG. 7, theapparatus includes an obtaining module 21 and a processing module 22.The obtaining module 21 is configured to obtain transmit power in asymbol overlapping portion of a first subframe and a second subframe,where the first subframe is a subframe in which a SRS is transmitted ona first carrier, and the second subframe is a subframe in which an SRSor a physical channel is transmitted on a second carrier. The processingmodule 22 is configured to, if the transmit power is greater thanmaximum transmit power of UE, control transmit power for ato-be-transmitted signal, where the to-be-transmitted signal includesthe SRS and/or the physical channel.

Optionally, the processing module 22 is further configured to determinewhether the SRS is configured periodically or configured aperiodically.

Optionally, that the processing module 22 controls transmit power for ato-be-transmitted signal includes that the processing module 22 controlsthe transmit power for the to-be-transmitted signal based on aperiodical configuration of the SRS, or that the processing module 22controls the transmit power for the to-be-transmitted signal based on anaperiodical configuration of the SRS.

Optionally, if the SRS is configured periodically, that the processingmodule 22 controls transmit power for a to-be-transmitted signalincludes that the processing module 22 drops the SRS or performs powerscaling for the SRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH does not include UCI, that the processingmodule 22 controls transmit power for a to-be-transmitted signalincludes that the processing module 22 drops the PUSCH or performs powerscaling for the PUSCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH includes UCI, that the processing module 22controls transmit power for a to-be-transmitted signal includes that theprocessing module 22 drops the SRS or performs power scaling for theSRS.

Optionally, if the SRS is configured aperiodically, and the physicalchannel is a PUCCH, that the processing module 22 controls transmitpower for a to-be-transmitted signal includes that the processing module22 drops the SRS or performs power scaling for the SRS, or that theprocessing module 22 drops the PUCCH or performs power scaling for thePUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes a HARQ, that the processing module 22controls transmit power for a to-be-transmitted signal includes that theprocessing module 22 drops the SRS or performs power scaling for theSRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes only CSI, that the processing module22 controls transmit power for a to-be-transmitted signal that theprocessing module 22 drops the SRS or performs power scaling for theSRS, or that the processing module 22 drops the PUCCH or performs powerscaling for the PUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PRACH, and the PRACH is concurrent, that the processing module 22controls transmit power for a to-be-transmitted signal includes that theprocessing module 22 drops the SRS or performs power scaling for theSRS.

The apparatus in this embodiment may be configured to execute thetechnical solution of the method embodiment shown in FIG. 4. Theirimplementation principles and technical effects are similar, and no moredetails are provided herein.

FIG. 8 is a structural diagram of a power control apparatus according toEmbodiment 7 of the present disclosure. As shown in FIG. 8, theapparatus includes an obtaining module 31 and a sending module 32. Theobtaining module 31 is configured to obtain a power control parameterfor a SRS on a first carrier, where the power control parameter for theSRS includes at least one of a target power parameter value for the SRS,a path loss compensation factor, and a closed-loop power controlparameter value for the SRS. The sending module 32 is configured to sendthe power control parameter for the SRS to UE such that the UEdetermines transmit power for the SRS on the first carrier based on thepower control parameter for the SRS.

Optionally, the first carrier is a carrier on which no PUSCH is sent.

Optionally, the sending module is further configured to send the powercontrol parameter for the SRS to the UE using power control signaling orcross-carrier power control signaling.

Optionally, the power control signaling includes open-loop power controlsignaling and/or closed-loop power control signaling.

Optionally, the power control signaling or the cross-carrier powercontrol signaling includes RRC signaling or physical layer signaling.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

Optionally, that the sending module sends the power control parameterfor the SRS to the UE using power control signaling or cross-carrierpower control signaling includes that the sending module scrambles thepower control parameter for the SRS based on a first RNTI, to generatethe power control signaling or the cross-carrier power controlsignaling, and sends the power control signaling or the cross-carrierpower control signaling to the UE.

Optionally, the SRS is configured periodically or configuredaperiodically.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the closed-looppower control parameter value for the SRS is an absolute value or arelative adjustment value.

Optionally, the sending module is further configured to send TPCinformation to the UE such that the UE parses out the closed-loop powercontrol parameter value for the SRS from the TPC information, where theTPC information is information scrambled with the first RNTI.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter for the SRS, the sending module isfurther configured to send DCI to the UE such that the UE obtains theclosed-loop power control parameter value for the SRS based on the DCI.

Optionally, if the DCI is control information obtained on a secondcarrier, the DCI includes at least a first carrier index, and the DCI isused to instruct the UE to obtain the closed-loop power controlparameter value for the SRS on a carrier corresponding to the firstcarrier index.

Optionally, the second carrier is a switching-from carrier or anycarrier other than a switched-to carrier, and the first carrier is theswitched-to carrier.

Optionally, if the DCI is control information obtained on the firstcarrier, the DCI is used to instruct the UE to obtain the closed-looppower control parameter value for the SRS from the DCI.

The apparatus in this embodiment may be configured to execute thetechnical solution of the method embodiment shown in FIG. 5. Theirimplementation principles and technical effects are similar, and no moredetails are provided herein.

FIG. 9 is a structural diagram of UE according to Embodiment 8 of thepresent disclosure. The UE may include a processor 401 and a memory 402.The apparatus may further include a transmit interface 403 and a receiveinterface 404. The transmit interface 403 and the receive interface 404may be connected to the processor 401. The transmit interface 403 isused to send data or information, and the transmit interface 403 may bea radio transmitting apparatus. The receive interface 404 is used toreceive data or information, and the receive interface 404 may be aradio receiving apparatus. The memory 402 stores an executableinstruction. When the apparatus runs, the processor 401 communicateswith the memory 402, and the processor 401 call the executableinstruction in the memory 402 to perform the following operationsobtaining a power control parameter for a SRS, where the power controlparameter for the SRS includes at least one of a target power parametervalue for the SRS, a path loss compensation factor, and a closed-looppower control parameter value for the SRS, and determining transmitpower for the SRS on a first carrier based on the power controlparameter for the SRS.

Optionally, the first carrier is a carrier on which no PUSCH is sent.

Optionally, that the processor 401 obtains a power control parameter fora SRS includes that the processor 401 receives power control signalingor cross-carrier power control signaling sent by a base station.

Optionally, the power control signaling includes open-loop power controlsignaling and/or closed-loop power control signaling.

Optionally, that the processor 401 obtains a power control parameter fora SRS includes that the processor 401 obtains the power controlparameter for the SRS from the power control signaling or thecross-carrier power control signaling.

Optionally, the power control signaling or the cross-carrier powercontrol signaling includes RRC signaling or physical layer signaling.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

Optionally, that the processor 401 obtains the power control parameterfrom the power control signaling or the cross-carrier power controlsignaling includes that the processor 401 parses out the power controlparameter for the SRS from the power control signaling or thecross-carrier power control signaling based on a first RNTI.

Optionally, that the processor 401 determines transmit power for the SRSbased on the power control parameter for the SRS includes that theprocessor 401 obtains the transmit power for the SRS based on at leastone of maximum transmit power of UE, a transmit power adjustment valuefor the SRS, transmission bandwidth for the SRS, the target powerparameter value for the SRS, the path loss compensation factor, and anestimated downlink path loss value.

Optionally, that the processor 401 determines transmit power for the SRSbased on the power control parameter for the SRS includes that theprocessor 401 calculates the transmit power P_(SRS,c1)(i) for the SRSaccording to a formula P_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)}, where P_(CMAX,c1)(i) is maximumtransmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, where j equals 0, 1, or 2, α_(SRS,c1)(j) is the path losscompensation factor, and PL_(SRS,c1) is the estimated downlink path lossvalue.

Optionally, the processor 401 is further configured to determine whetherthe SRS is configured periodically or configured aperiodically.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the closed-looppower control parameter value for the SRS is an absolute value or arelative adjustment value.

Optionally, the processor 401 is further configured to obtain TPCinformation, where the TPC information is information scrambled with thefirst RNTI.

Optionally, the processor 401 is further configured to parse out theclosed-loop power control parameter value for the SRS from the TPCinformation based on the first RNTI.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the processor 401is further configured to obtain DCI.

Optionally, that the processor 401 obtains the power control parameterfor the SRS includes that the processor 401 obtains the closed-looppower control parameter value for the SRS based on the DCI.

Optionally, if the DCI is control information obtained on a secondcarrier, the DCI includes at least a first carrier index.

Optionally, the second carrier is a switching-from carrier or anycarrier other than a switched-to carrier, and the first carrier is theswitched-to carrier.

Optionally, that the processor 401 obtains the closed-loop power controlparameter value for the SRS based on the DCI includes that the processor401 obtains the closed-loop power control parameter value for the SRS ona carrier corresponding to the first carrier index.

Optionally, if the DCI is control information obtained on the firstcarrier, that the processor 401 obtains the closed-loop power controlparameter value for the SRS based on the DCI includes that the processor401 obtains the closed-loop power control parameter value for the SRSfrom the DCI.

Optionally, if the closed-loop power control parameter value for the SRSis a relative adjustment value, the processor 401 is further configuredto determine the closed-loop power control parameter value for the SRSbased on at least one of closed-loop power control information or arelative adjustment value for an SRS in a previous subframe.

Optionally, that the processor 401 determines the closed-loop powercontrol parameter for the SRS based on at least one of closed-loop powercontrol information or a relative adjustment value for an SRS in aprevious subframe includes that the processor 401 calculates theclosed-loop power control parameter value f_(SRS,c1)(i) for the SRSaccording to a formulaf_(SRS,c1)(i)=f_(SRS,c1)(i−1)+δ_(SRS,c1)(i−K_(SRS)), wheref_(SRS,c1)(i−1) is the closed-loop power control information for the SRSin the previous subframe δ_(SRS,c1)(i−K_(SRS)) is the relativeadjustment value, and if the SRS is configured periodically, K_(SRS) isa subframe periodicity of the SRS, or if the SRS is configuredaperiodically, i—K_(SRS) is a subframe number of the previous subframe.

Optionally, that the processor 401 determines transmit power for the SRSbased on the power control parameter for the SRS includes that theprocessor 401 obtains the transmit power for the SRS based on at leastone of maximum transmit power of the UE, a transmit power adjustmentvalue for the SRS, transmission bandwidth for the SRS, the target powerparameter value for the SRS, the path loss compensation factor, theestimated downlink path loss value, and a closed-loop power controlparameter for the SRS.

Optionally, that the processor 401 determines transmit power for the SRSbased on the power control parameter for the SRS includes that theprocessor 401 calculates the transmit power P_(SRS,c1)(i) for the SRSaccording to a formula P_(SRS,c1)(i)=min{P_(CMAX,c1)(i), P_(SRS) _(_)_(OFFSET,c1)(m)+10log₁₀(M_(SRS,c1))+P_(O) _(_)_(SRS,c1)(j)+α_(SRS,c1)(j)·PL_(SRS,c1)+f_(SRS,c1)}, where P_(CMAX,c1)(i)is maximum transmit power of the UE in an i^(th) subframe, P_(SRS) _(_)_(OFFSET,c1)(m) is the transmit power adjustment value for the SRS,where m equals 0 or 1, M_(SRS,c1) is the transmission bandwidth for theSRS, P_(O) _(_) _(SRS,c1)(j) is the target power parameter value for theSRS, α_(SRS,c1)(j) is the path loss compensation factor, PL_(SRS,c1) isthe estimated downlink path loss value, and f_(SRS,c1)(i) is theclosed-loop power control parameter value for the SRS.

The UE in this embodiment may be configured to execute the technicalsolution of the method embodiment shown in FIG. 2 or FIG. 3. Theirimplementation principles and technical effects are similar, and no moredetails are provided herein.

An embodiment of this application further provides UE, where a structureof the UE is the same as a structure of the UE shown in FIG. 9. When theUE runs, a processor communicates with a memory, and the processor callsan executable instruction in the memory to perform the followingoperations obtaining transmit power in a symbol overlapping portion of afirst subframe and a second subframe, where the first subframe is asubframe in which a SRS is transmitted on a first carrier, and thesecond subframe is a subframe in which an SRS or a physical channel istransmitted on a second carrier, and if the transmit power is greaterthan maximum transmit power of the UE, controlling transmit power for ato-be-transmitted signal, where the to-be-transmitted signal includesthe SRS and/or the physical channel.

Optionally, the processor is further configured to determine whether theSRS is configured periodically or configured aperiodically.

Optionally, that the processor controls transmit power for ato-be-transmitted signal includes that the processor controls thetransmit power for the to-be-transmitted signal based on a periodicalconfiguration of the SRS, or that the processor controls the transmitpower for the to-be-transmitted signal based on an aperiodicalconfiguration of the SRS.

Optionally, if the SRS is configured periodically, that the processorcontrols transmit power for a to-be-transmitted signal includes thatdropping the SRS or performing power scaling for the SRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH does not include UCI, that the processorcontrols transmit power for a to-be-transmitted signal includes that theprocessor drops the PUSCH or performs power scaling for the PUSCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUSCH, and the PUSCH includes UCI, that the processor controlstransmit power for a to-be-transmitted signal includes that theprocessor drops the SRS or performs power scaling for the SRS.

Optionally, if the SRS is configured aperiodically, and the physicalchannel is a PUCCH, that the processor controls transmit power for ato-be-transmitted signal includes that the processor drops the SRS orperforms power scaling for the SRS, or that the processor drops thePUCCH or performs power scaling for the PUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes a HARQ, that the processor controlstransmit power for a to-be-transmitted signal includes that theprocessor drops the SRS or performs power scaling for the SRS.

Optionally, if the SRS is configured aperiodically, the physical channelis a PUCCH, and the PUCCH includes only CSI, that the processor controlstransmit power for a to-be-transmitted signal includes that theprocessor drops the SRS or performs power scaling for the SRS, or thatthe processor drops the PUCCH or performs power scaling for the PUCCH.

Optionally, if the SRS is configured aperiodically, the physical channelis a PRACH, and the PRACH is concurrent, that the processor controlstransmit power for a to-be-transmitted signal includes that theprocessor drops the SRS or performs power scaling for the SRS.

The UE in this embodiment may be configured to execute the technicalsolution of the method embodiment shown in FIG. 4. Their implementationprinciples and technical effects are similar, and no more details areprovided herein.

FIG. 10 is a structural diagram of a base station according toEmbodiment 9 of the present disclosure. As shown in FIG. 10, the basestation includes a processor 501 and a transmitter 502. The processor501 is configured to obtain a power control parameter for a SRS on afirst carrier, where the power control parameter for the SRS includes atleast one of a target power parameter value for the SRS, a path losscompensation factor, and a closed-loop power control parameter value forthe SRS. The transmitter 502 is configured to send the power controlparameter for the SRS to UE such that the UE determines transmit powerfor the SRS on the first carrier based on the power control parameterfor the SRS.

Optionally, the first carrier is a carrier on which no PUSCH is sent.

Optionally, that the transmitter 502 sends the power control parameterfor the SRS to UE includes that the transmitter 502 sends the powercontrol parameter for the SRS to the UE using power control signaling orcross-carrier power control signaling.

Optionally, the power control signaling includes open-loop power controlsignaling and/or closed-loop power control signaling.

Optionally, the power control signaling or the cross-carrier powercontrol signaling includes RRC signaling or physical layer signaling.

Optionally, the target power parameter value for the SRS is a parametervalue obtained based on a preamble initial received target power value,or the target power parameter value for the SRS is a parameter valueobtained based on a preamble initial received target power value and apower adjustment value.

Optionally, that the transmitter 502 sends the power control parameterfor the SRS to the UE using power control signaling or cross-carrierpower control signaling includes that the transmitter 502 scrambles thepower control parameter for the SRS based on an RNTI, to generate thepower control signaling or the cross-carrier power control signaling,and sending the power control signaling or the cross-carrier powercontrol signaling to the UE.

Optionally, the SRS is configured periodically or configuredaperiodically.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter value for the SRS, the closed-looppower control parameter value for the SRS is an absolute value or arelative adjustment value.

Optionally, the transmitter 502 is further configured to send TPCinformation to the UE such that the UE parses out the closed-loop powercontrol parameter value for the SRS from the TPC information, where theTPC information is information scrambled with the first RNTI.

Optionally, if the power control parameter for the SRS includes theclosed-loop power control parameter for the SRS, the transmitter 502 isfurther configured to send DCI to the UE such that the UE obtains theclosed-loop power control parameter value for the SRS based on the DCI.

Optionally, if the DCI is control information obtained on a secondcarrier, the DCI includes at least a first carrier index, and the DCI isused to instruct the UE to obtain the closed-loop power controlparameter value for the SRS on a carrier corresponding to the firstcarrier index.

Optionally, the second carrier is a switching-from carrier or anycarrier other than a switched-to carrier, and the first carrier is theswitched-to carrier.

Optionally, if the DCI is control information obtained on the firstcarrier, the DCI is used to instruct the UE to obtain the closed-looppower control parameter value for the SRS from the DCI.

Optionally, as shown in FIG. 10, the base station may further include amemory 503 and a receiver 504. The memory 503 is configured to store aninstruction and data, and the receiver 504 is configured to receive dataor information.

The apparatus in this embodiment may be configured to execute thetechnical solution of the method embodiment shown in FIG. 5. Theirimplementation principles and technical effects are similar, and no moredetails are provided herein.

Persons of ordinary skill in the art may understand that all or some ofthe steps of the method embodiments may be implemented by a programinstructing relevant hardware. The program may be stored in acomputer-readable storage medium. When the program runs, the steps ofthe method embodiments are performed. The foregoing storage mediumincludes any medium that can store program code, such as a read-onlymemory, a random access memory, a magnetic disk, or an optical disc.

Finally, it should be noted that the foregoing embodiments are merelyintended for describing the technical solutions of the presentdisclosure, but not for limiting the present disclosure. Although thepresent disclosure is described in detail with reference to theforegoing embodiments, persons of ordinary skill in the art shouldunderstand that they may still make modifications to the technicalsolutions described in the foregoing embodiments or make equivalentreplacements to some or all technical features thereof, withoutdeparting from the scope of the technical solutions of the embodimentsof the present disclosure.

What is claimed is:
 1. A power control method, comprising: obtainingRadio Resource Control (RRC) signalling, wherein the RRC signallingcomprises a target power parameter value for a sounding reference signal(SRS) and a path loss compensation factor for the SRS; obtainingdownlink control information (DCI); obtaining a closed-loop powercontrol parameter value for the SRS based on the DCI, wherein theclosed-loop power control parameter value for the SRS corresponds to afirst carrier index, wherein the first carrier index identifies a firstcarrier on which no physical uplink shared channel (PUSCH) is sent; anddetermining a first transmit power for the SRS on the first carrierbased on the target power parameter value, the path loss compensationfactor, and the closed-loop power control parameter value.
 2. The powercontrol method of claim 1, wherein the first carrier is a switched-tocarrier of SRS carrier switching.
 3. The power control method of claim1, wherein obtaining the closed-loop power control parameter value forthe SRS based on the DCI comprises: obtaining transmission power control(TPC) information from the DCI, wherein the TPC information is scrambledwith a first radio network temporary identifier (RNTI), and wherein thefirst RNTI is TPC-SRS-RNTI; and parsing the closed-loop power controlparameter value for the SRS from the TPC information based on the firstRNTI.
 4. The power control method of claim 1, wherein before determiningthe first transmit power for the SRS on the first carrier based on thetarget power parameter value, the path loss compensation factor and theclosed-loop power control parameter value, the power control methodfurther comprises determining a configuration of the SRS, wherein theconfiguration of the SRS is periodic or aperiodic, and whereindetermining the first transmit power for the SRS on the first carrierbased on the target power parameter value, the path loss compensationfactor and the closed-loop power control parameter value comprisesdetermining the first transmit power for the SRS on the first carrierbased on the target power parameter value, the path loss compensationfactor, the closed-loop power control parameter value and theconfiguration of the SRS.
 5. The power control method of claim 1,further comprising: obtaining a second transmit power in a symboloverlapping portion of a first subframe and a second subframe, whereinthe first subframe carries the SRS on the first carrier, and wherein thesecond subframe carries a physical channel on a second carrier; andcontrolling a third transmit power for a to-be-transmitted signal,wherein the to-be-transmitted signal comprises the SRS or the physicalchannel.
 6. The power control method of claim 5, wherein beforecontrolling the third transmit power for the to-be-transmitted signal,the power control method comprises determining whether the SRS is aperiodically configured SRS or an aperiodically configured SRS.
 7. Thepower control method of claim 6, wherein controlling the third transmitpower for the to-be-transmitted signal comprises one of: dropping aphysical uplink control channel (PUCCH) when the SRS is theaperiodically configured SRS and the physical channel is the PUCCH;dropping the SRS when the SRS is the aperiodically configured SRS andthe physical channel is the PUCCH, wherein the PUCCH comprises a hybridautomatic repeat request (HARQ); dropping the PUCCH when the SRS is theaperiodically configured SRS and the physical channel is the PUCCH,wherein the PUCCH comprises only channel state information (CSI); ordropping the SRS when the SRS is the aperiodically configured SRS andthe physical channel is a packet random access channel (PRACH), whereinthe PRACH is concurrent.
 8. A computer program product comprisingcomputer-executable instructions for storage on a non-transitorycomputer-readable medium that, when executed by a processor, cause anelectronic device to: obtain Radio Resource Control (RRC) signalling,wherein the RRC signalling comprises a target power parameter value fora sounding reference signal (SRS) and a path loss compensation factorfor the SRS; obtain downlink control information (DCI); obtain aclosed-loop power control parameter value for the SRS based on the DCI,wherein the closed-loop power control parameter value for the SRScorresponds to a first carrier index, and wherein the first carrierindex identifies a first carrier on which no physical uplink sharedchannel (PUSCH) is sent; and determine a first transmit power for theSRS on the first carrier based on the target power parameter value, thepath loss compensation factor and the closed-loop power controlparameter value.
 9. The computer program product of claim 8, wherein thefirst carrier is a switched-to carrier of SRS carrier switching.
 10. Thecomputer program product of claim 8, wherein obtaining the closed-looppower control parameter value for the SRS based on the DCI comprises:obtaining transmission power control (TPC) information from the DCI,wherein the TPC information is information scrambled with a first radionetwork temporary identifier (RNTI), wherein the first RNTI isTPC-SRS-RNTI; and parsing the closed-loop power control parameter valuefor the SRS from the TPC information based on the first RNTI.
 11. Thecomputer program product of claim 8, wherein before determining thefirst transmit power for the SRS on the first carrier based on thetarget power parameter value, the path loss compensation factor and theclosed-loop power control parameter value, the computer-executableinstructions further cause the electronic device to determine aconfiguration of the SRS, wherein the configuration of the SRS is eitherperiodic configuration of the SRS or aperiodic configuration of the SRS,and wherein determining the first transmit power for the SRS on thefirst carrier based on the target power parameter value, the path losscompensation factor, and the closed-loop power control parameter valuecomprises determining the first transmit power for the SRS on the firstcarrier based on the target power parameter value, the path losscompensation factor, the closed-loop power control parameter value, andthe configuration of the SRS.
 12. The computer program product of claim8, wherein the computer-executable instructions further cause theelectronic device to: obtain a second transmit power in a symboloverlapping portion of a first subframe and a second subframe, whereinthe first subframe carries the SRS on the first carrier, and wherein thesecond subframe carries a physical channel on a second carrier; andcontrol a third transmit power for a to-be-transmitted signal, whereinthe to-be-transmitted signal comprises the SRS or the physical channel.13. The computer program product of claim 12, wherein before controllingthe third transmit power for the to-be-transmitted signal, thecomputer-executable instructions further cause the electronic device todetermine whether the SRS is a periodically configured SRS or anaperiodically configured SRS.
 14. The computer program product of claim13, wherein the instructions further cause the electronic device toperform one of: drop a physical uplink control channel (PUCCH) when theSRS is an aperiodically configured SRS and the physical channel is thePUCCH; drop the SRS when the SRS is an aperiodically configured SRS andthe physical channel is a PUCCH, wherein the PUCCH comprises a hybridautomatic repeat request (HARD); drop the PUCCH when the SRS is anaperiodically configured SRS and the physical channel is a PUCCH,wherein the PUCCH comprises only channel state information (CSI); ordrop the SRS when the SRS is an aperiodically configured SRS, thephysical channel is a packet random access channel PRACH, and the PRACHis concurrent.
 15. An apparatus, comprising instructions which, whenexecuted by an electronic device, cause the electronic device to: obtainRadio Resource Control (RRC) signalling, wherein the RRC signallingcomprises a target power parameter value for a sounding reference signal(SRS) and a path loss compensation factor for the SRS; obtain downlinkcontrol information (DCI); obtain a closed-loop power control parametervalue for the SRS based on the DCI, wherein the closed-loop powercontrol parameter value for the SRS corresponds to a first carrierindex, wherein the first carrier index identifies a first carrier onwhich no physical uplink shared channel (PUSCH) is sent; and determine afirst transmit power for the SRS on the first carrier based on thetarget power parameter value, the path loss compensation factor, and theclosed-loop power control parameter value.
 16. The apparatus of claim15, wherein the apparatus is a chip.
 17. The apparatus of claim 15,wherein the first carrier is a switched-to carrier of SRS carrierswitching.
 18. The apparatus of claim 15, wherein obtaining theclosed-loop power control parameter value for the SRS based on the DCIcomprises: obtaining transmission power control (TPC) information fromthe DCI, wherein the TPC information is information scrambled with afirst radio network temporary identifier (RNTI), and wherein the firstRNTI is TPC-SRS-RNTI; and parsing the closed-loop power controlparameter value for the SRS from the TPC information based on the firstRNTI.
 19. The apparatus of claim 15, wherein before determining thefirst transmit power for the SRS on the first carrier based on thetarget power parameter value, the path loss compensation factor and theclosed-loop power control parameter value, the instructions furthercause the electronic device to be configured to determine aconfiguration of the SRS, wherein the configuration of the SRS is eitherperiodic configuration of the SRS or aperiodic configuration of the SRSand wherein determining the first transmit power for the SRS on thefirst carrier based on the target power parameter value, the path losscompensation factor and the closed-loop power control parameter valuedetermining the first transmit power for the SRS on the first carrierbased on the target power parameter value, the path loss compensationfactor, the closed-loop power control parameter value, and theconfiguration of the SRS.
 20. The apparatus of claim 15, wherein theinstructions further cause the electronic device to be configured to:obtain a second transmit power in a symbol overlapping portion of afirst subframe and a second subframe, wherein the first subframe carriesthe SRS on the first carrier, and the second subframe carries a physicalchannel on a second carrier; and control a third transmit power for ato-be-transmitted signal, wherein the to-be-transmitted signal comprisesthe SRS or the physical channel.
 21. The apparatus of claim 20, whereinbefore controlling the third transmit power for the to-be-transmittedsignal, the instructions further cause the electronic device to beconfigured to determine whether the SRS is a periodically configured SRSor an aperiodically configured SRS.
 22. The apparatus of claim 21,wherein the instructions further cause the device to perform one of:drop a physical uplink control channel (PUCCH) when the SRS is anaperiodically configured SRS, wherein the physical channel is the PUCCH;drop the SRS when the SRS is an aperiodically configured SRS and thephysical channel is a PUCCH, wherein the PUCCH comprises a hybridautomatic repeat request (HARQ); drop the PUCCH when the SRS is anaperiodically configured SRS and the physical channel is a PUCCH,wherein the PUCCH comprises only channel state information (CSI); ordrop the SRS when the SRS is an aperiodically configured SRS, thephysical channel is a packet random access channel (PRACH), and thePRACH is concurrent.
 23. A user equipment (UE), comprising: one or moreprocessors; and a memory coupled to the one or more processors,including instructions that when executed by the one or more processors,cause the UE to be configured to: obtain Radio Resource Control (RRC)signalling, wherein the RRC signalling comprises a target powerparameter value for a sounding reference signal (SRS) and a path losscompensation factor for the SRS; obtain downlink control information(DCI); obtain a closed-loop power control parameter value for the SRSbased on the DCI, wherein the closed-loop power control parameter valuefor the SRS corresponds to a first carrier index, wherein the firstcarrier index identifies a first carrier on which no physical uplinkshared channel (PUSCH) is sent; and determine a first transmit power forthe SRS on the first carrier based on the target power parameter value,the path loss compensation factor and the closed-loop power controlparameter value.
 24. The UE of claim 23, wherein the first carrier is aswitched-to carrier of SRS carrier switching.
 25. The UE of claim 23,wherein obtaining the closed-loop power control parameter value for theSRS based on the DCI comprises: obtaining transmission power control(TPC) information from the DCI, wherein the TPC information isinformation scrambled with a first radio network temporary identifier(RNTI), and wherein the first RNTI is TPC-SRS-RNTI; and parsing theclosed-loop power control parameter value for the SRS from the TPCinformation based on the first RNTI.
 26. The UE of claim 23, whereinbefore determining the first transmit power for the SRS on the firstcarrier based on the target power parameter value, the path losscompensation factor and the closed-loop power control parameter value,wherein the instructions further cause the UE to be configured todetermine a configuration of the SRS, wherein the configuration of theSRS is either periodic configuration of the SRS or aperiodicconfiguration of the SRS and wherein determining the first transmitpower for the SRS on the first carrier based on the target powerparameter value, the path loss compensation factor and the closed-looppower control parameter value comprises determining the first transmitpower for the SRS on the first carrier based on the target powerparameter value, the path loss compensation factor, the closed-looppower control parameter value, and the configuration of the SRS.
 27. TheUE of claim 23, wherein the instructions further cause the UE to beconfigured to: obtain a second transmit power in a symbol overlappingportion of a first subframe and a second subframe, wherein the firstsubframe carries the SRS on the first carrier, and wherein the secondsubframe carries a physical channel on a second carrier; and control athird transmit power for a to-be-transmitted signal, wherein theto-be-transmitted signal comprises the SRS or the physical channel. 28.The UE of claim 27, wherein before controlling the third transmit powerfor the to-be-transmitted signal, the instructions further cause the UEto be configured to determine whether the SRS is a periodicallyconfigured SRS or an aperiodically configured SRS.
 29. The UE of claim28, wherein controlling the third transmit power for theto-be-transmitted signal comprises one of: drop a physical uplinkcontrol channel (PUCCH) when the SRS is the aperiodically configuredSRS, the PUCCH; drop the SRS when the SRS is the aperiodicallyconfigured SRS and the physical channel is the PUCCH, wherein the PUCCHcomprises a hybrid automatic repeat request (HARQ); drop the PUCCH whenthe SRS is the aperiodically configured SRS and the physical channel isthe PUCCH, wherein the PUCCH comprises only channel state information(CSI); or drop the SRS when the SRS is the aperiodically configured SRS,the physical channel is a packet random access channel (PRACH), and thePRACH is concurrent.